Proliant buying advice
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@Carnival-Boy said:
Also, would I be right in thinking that it is probably more economical to have a large number of 10k disks instead of a small number of 15k, given that 15k are nearly twice the price so I could have almost 16 x 10k disks instead of 8 x 15k?
Using the numbers in the post @scottalanmiller linked a few days back it looks like this.
8x drives:
16x drives:
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@Carnival-Boy said:
As I mentioned, the DBs will probably only reach around 20GB, so with 64GB RAM, SQL Server should place the entire DB into memory. I think that means disk performance won't matter (but I'm not sure on the technicalities).
That is mostly true, although writes always have to go to disk. That is where the 4GB cache, especially when assigned mostly to writes, can pay huge dividends.
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@Dashrender said:
If your DB is really only 20 Gig, you might be better off dumping the HDDs altogether and instead going with 2 SSDs in RAID 1. You'll have less heat, less power draw, WAY faster drives, etc.
This makes a lot of sense. Cheaper, many times faster.
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The databases are small, but there is a lot of other data that will need plenty of storage. I'm guessing that database performance is the bottleneck rather than general file serving and other miscellaneous applications, so if I take away that concern (by ensuring plenty of RAM), I'm not sure I should be too concerned with other disk performance issues.
Are you saying that the best bang for my buck could be buying a P440 rather than P440ar? There isn't a lot of difference in price, but double the amount of write cache (4GB versus 2GB). HP don't do a unit that comes pre-configured with a P440 for some reason.
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How much write cache do you have on the current machine?
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512mb, battery backed.
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The 4 GB cache along with your 8 drives will probably be enough, but without real metrics on what you new ERP's requirements will be, no one can be sure.
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@Dashrender said:
The 4 GB cache along with your 8 drives will probably be enough, but without real metrics on what you new ERP's requirements will be, no one can be sure.
It's amazing how much different a good cache can make.
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These are the controller options:
Can anyone tell me the difference between "Flexible" Smart Array Controllers and the others. What are the ports for (and why would I want 2 ports rather than 1)?
Will a 4GB always be faster than 2GB, or will it only have an effect if the 2GB gets filled whilst writing to disk and therefore has to wait (I'm not sure if I'm talking crap here or not)?
What is FIO?
And what does 'ar' stand for in the name P440ar?
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@Carnival-Boy said:
Will a 4GB always be faster than 2GB, or will it only have an effect if the 2GB gets filled whilst writing to disk and therefore has to wait (I'm not sure if I'm talking crap here or not)?
Not "always" but anytime that you are doing any amount of disk IO. If you don't have a total of 2GB of storage, for example, then 4GB of cache would be overkill. But given the size of modern storage (and certainly with your database being more than 2GB and your OS being larger than 2GB) you are into a range where yes, 4GB will always be faster. There is no situation where you will not use at least 2GB of disk reads or writes on any given boot up. That number is just so tiny compared to the size of your storage that while technically it might be too big for some workloads, no real world ones and certainly not yours. You would be safe buying 16GB or more of cache and knowing for certain that bigger kept meaning faster.
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FIO, I believe, refers to "Flexible IO" and means that it is neither internal nor external but has both. That's why you see internal, external or FIO as the options. Never Internal FIO or External FIO.
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Each port is another full SAS channel with full SAS bandwidth. You want that if you have a place to use it. You don't, so does not matter to you. It is often used when you have an internal array and an external array or a massive internal array that you want to split.
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I can't figure out what "ar" stands for but it appears that it means that it is a mezzanine card rather than an add on card.
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Hmm.... not sure then. HP is bad about listing their acronyms anywhere.
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@scottalanmiller said:
I can't figure out what "ar" stands for but it appears that it means that it is a mezzanine card rather than an add on card.
Ah, I see. It does look different:
I'm advised that I can't currently get a DL380 without a P440ar/2GB, so it would be a case of throwing it away and replacing it with a P440/4GB. I'd effectively be buying two cards, even though I only used one. I'm not sure it's worth it.
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Is it possible to simply upgrade the RAID controller at a later date if performance becomes a problem, or does that incur a world of pain?
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@Carnival-Boy said:
Is it possible to simply upgrade the RAID controller at a later date if performance becomes a problem, or does that incur a world of pain?
Generally pretty painless. Since they are both SmartArrays.
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Cool. I might do that, then. Though those kinds of upgrades always scare me.
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2GB of cache is still four times what you have now and twice what most anyone else has.
